Mass evacuation under way in Bundaberg

The race is on to evacuate thousands of people from parts of Bundaberg, with the Queensland premier warning torrents of water could wash houses away.

Campbell Newman says aircraft are being scrambled to get people out of north Bundaberg and other low-lying parts of the city before nightfall.

The city has been hit by a record flood, with about 2000 properties already affected by flooding and waters still rising.

"We are going to endeavour to get every single person to safety by nightfall tonight," Mr Newman told reporters on Monday afternoon.

Once it's dark, it would be up to pilots to decide whether they attempt dangerous night-time rescues, he said.

The speed of water moving through some parts of the city is estimated at 40 knots, or almost 75km/h.

"The velocity of the water, and the rises in the water levels, means that literally houses, particularly in north Bundaberg, and maybe other locations, could be swept away," the premier said.

Earlier on Monday, mandatory evacuation orders were made for north Bundaberg, and low-lying parts of the city's south and east. Some people have already left but some have not.

Mr Newman says Bundaberg is at the centre of the emergency response, but with so many other communities also affected the tempo of the state's latest disaster is increasing.

The city of Ipswich is beginning to flood, with some businesses in the CBD already underwater after the Bremer River broke its banks. Up to 350 properties in Ipswich could be affected.

There's already localised flooding in some parts of Brisbane, with a flood peak in the Brisbane River due at noon on Tuesday.

About 5000 homes and businesses could face some level of flooding but the damage in Brisbane and Ipswich is not going to be anything like it was in 2011, the premier says.

The communities of Gympie and Maryborough are flooding, Gladstone had suffered severe flooding downstream from Awoonga dam, and Rockhampton was braced for a significant flood from this weekend.

Three people have already died in Queensland: a motorcyclist whose body was pulled from the Oxley Creek south of Brisbane, an 81-year-old man whose body was found near Bundaberg, and a 27-year-old man who tried to cross a flooded creek near Gympie.

The low-pressure system that was cyclone Oswald has now crossed the NSW border, bringing 1400 calls for help and more than a dozen swift-water rescues in the state's north.

About 2000 people are cut off in NSW's north and flood warnings are in place for seven NSW river systems.

The immediate threat is for flooding near the Tweed River, Wilsons and Richmond Rivers and the Clarence Valley.

Major population centres, including Sydney, are on alert for severe weather.

Prime Minister Julia Gillard said the disaster in Queensland was heartbreaking so soon after the deadly 2011 floods.

As she toured bushfire-ravaged communities in Victoria, she said nature was challenging the nation.

"Across Queensland the wild weather has broken a lot of hearts. It's a very tough period," she said, and repeated promises of federal help as the state recovers.

The Queensland premier again assured Ipswich and Brisbane residents the flood would be nothing like what was seen in 2011 but some damage was unavoidable.

But he said the two cities, like others affected by the disaster, would get all the help they need to recover.

"To those right now, in the grip of this disaster, I say to you: 'You are not alone'. This state and its people will rise to the challenge I am supremely confident of that.

"We'll do whatever we can to protect you, in some cases to rescue you, and to do everything to stand by you in the days, weeks and months ahead. Together we will get through this."

AAP

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